Sources connected with the Bryant family tell TMZ … the dispute between mother and son erupted over real estate. We’re told Kobe offered to buy his parents a “nice house” in Vegas for significantly less than a million bucks, but they wanted something bigger and more extravagant and Kobe drew a line in the sand and refused to up the ante.

Our sources say Pamela was infuriated and believed Kobe was shortchanging them, especially compared to what he does for Vanessa’s mom, Sofia Laine. Kobe put Sofia up in a $3.2 million house in Newport Beach, CA, which sold recently. After the sale, Kobe moved Sofia to another multi-million dollar mansion nearby.

From Kobe’s perspective, our sources say he’s really upset because he believes he’s stepped up for years, by giving his parents millions of dollars and buying them homes and cars.

This feud has been brewing for years … dating back to when Kobe’s parents went ballistic when he married Vanessa without a prenup.

We don’t care WHAT type of bad relationship you have with your parents, to have your in-laws living in the lap of luxury and leave your mother and father scrambling to find money for a house is foul! What the hell has Vanessa parents done to deserve part of Kobe’s fortune that his parents have not??